Convert rich text to simple text (report designer)

I have a detailed answer for this question on Stack Overflow:

https://stackoverflow.com/a/59869303/7376238

The solution is to create a custom field and use the Html2PlainText helper method to extract the text content from the HTML field (body):

#region DescriptionAsPlainText
public abstract class descriptionAsPlainText : PX.Data.BQL.BqlString.Field<descriptionAsPlainText> { }

private string _plainText;
[PXString(IsUnicode = true)]
[PXUIField(Visible = false)]
public virtual String DescriptionAsPlainText
{
    get
    {
        return _plainText ?? (_plainText = PX.Data.Search.SearchService.Html2PlainText(this.Description));
    }
}
#endregion